You can download and install the Unity Editor from the Unity Website; unity3d.com/download.
The installer uses a Download Assistant and has detailed instructions to follow. (If you want to download the Unity editor using a torrent or install several versions of Unity at once, you can find out about this via Torrent Download below.)
From Unity version 5.0 onwards, the Unity Download Assistant, a small executable program (approximately 1 MB in size), lets you select which components of the Unity editor you want to download and install. If you are not sure which components you want to install, leave the default selections and click on Continue, following the installer’s instructions.
If you prefer, you can download and install all the components separately, without using the Download Assistant. The components are normal installer executable programs and packages, so you may find it simpler, especially if you are a new Unity user, to use the Download Assistant. Some users, such as those wishing to automate deployment of Unity in an organization, may prefer to install from the command line.
The following options can be used when installing the Unity Editor and other components from command line on Windows. Note that installer command line arguments are case-sensitive.
|/S||Performs a silent (no questions asked) install.|
|/D=PATH||Sets the default install directory. Useful when combined with the silent install option. Default folder is
UnitySetup64.exe /S /D=E:\Development\Unity
Install Unity silently to the folder E:\Development\Unity, which will be the root of the Unity installation. The Unity editor executable will in this case be installed in E:\Development\Unity\Editor\Unity.exe. “/D” argument must be last and without quotes, even if path contains spaces.
Silent uninstall can be performed using the following steps:
Uninstall.exe /Se.g. from command line or a script
Note, although the process will finish right away, it takes a few seconds before the files actually have been removed. The reason for this is that the uninstaller is copied to a temporary location, in order to be able to remove itself. Also make sure the working directory is not inside the Unity install location, as it won’t be able to remove the folder in that case.
Silently install webplayer (No option to specify install folder):
Silently install Standard Assets. If specifying folder, use the Unity “root” folder, i.e. the folder containing Editor folder and not where Unity.exe is installed into.
UnityStandardAssetsSetup.exe /S /D=E:\Development\Unity
Silently install Example Project. Default folder is C:\Users\Public\Documentation\Unity Projects\Standard Assets Example Project
UnityExampleProjectSetup.exe /S /D=E:\Development\Unity
The individual Unity installers are provided as .pkg files, which can be installed using
installer as described below.
Installs into folder
/Applications/Unity on the specified target volume:
sudo installer [-dumplog] -package Unity.pkg -target /
The Unity Web Player is installed in
/Library/Internet Plug-ins/Unity Web Player.plugin on Mac.
sudo installer [-dumplog] -package WebPlayer.pkg -target /
Installs into folder
/Applications/Unity/Standard Assets on the specified volume:
sudo installer [-dumplog] -package StandardAssets.pkg -target /
Install into folder
/Users/Shared/Unity/Standard-Assets on the specified volume:
sudo installer [-dumplog] -package Examples.pkg -target /
If you’d prefer to download Unity via a BitTorrent client, you can download get a Torrent link from our download archive page. Not all versions have a torrent download. If a version is available to download as a torrent, the option will be present in the “downloads” dropdown menu.
You can install as many versions of Unity as you like on the same computer. The installer on a Mac will always create a folder called “Unity” and will overwrite any existing folder with this name. However, if you rename the folder to something else before installing then both versions can happily live on the same computer. On a PC the install folder is always named “Unity X.Y.Z[fp]W”, where the ‘f’ is for an official release, and ‘p’ is used to mark a patch release.
We strongly recommend that you choose the new folder name carefully (eg, add the version number to the end of the name, “Unity4”, etc). Also, be aware that any existing shortcuts, aliases and links to the offline docs will no longer point to the old version of Unity. This can be particularly confusing with the offline docs; if you suddenly find that browser bookmarks to the offline docs no longer work then check that they have the right folder name in the URL.